Binding of sodium salicylate by beta-cyclodextrin or 2,6-di-O-methyl-beta-cyclodextrin in aqueous solution.
Speed of sound and conductivity experiments have been done at 298.15 K to study the encapsulation process of sodium salicylate (NaSA) by beta-cyclodextrin (beta-CD) and 2,6-di-O-methyl-beta-cyclodextrin (DIMEB) in aqueous solutions. Since the concentration of the salicyclic form (HSA), coming from the hydrolysis of SA-, is negligible at biological pH, the binding process studied in this work is that of the SA- species. The stoichiometries of the complexes DIMEB: SA- and beta-CD:SA- have been found to be 1:1, as usually determined for most CD:drug complexes. Their association constants and their ionic molar conductivities at infinite dilution have been obtained by fitting the experimental conductivity data with a nonlinear regression method (NLR). For that purpose, a model based on that of Gelb and co-workers has been used. From the values of K beta-CD:SA- = (105 +/- 15)M-1 and KDIMEB:SA- = (140 +/- 20)M-1 obtained, the bioavailability of the salicylate drug in the complexed form has been discussed.
Junquera
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Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense, Madrid, Spain.
Peña
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Aicart
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D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry*; D003217:Conductometry; D003505:Cyclodextrins / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D012980:Sodium Salicylate / Q000737:chemistry*; D012996:Solutions; D014867:Water; D047392:beta-Cyclodextrins
D000894:Anti-Inflammatory Agents, Non-Steroidal; D003505:Cyclodextrins; D012996:Solutions; D047392:beta-Cyclodextrins; D014867:Water; C038119:heptakis(2,6-O-dimethyl)beta-cyclodextrin; C031215:betadex; D012980:Sodium Salicylate